The news is that Daimler, Audi, and BMW have paid some US $3 billion for Here, Nokia’s road-mapping service. The question is why they did it.

Because of self-driving cars, you might respond. Well, yes, superaccurate road maps are increasingly useful to cars that think, serving as a kind of sixth sense (after radar, lidar, sonar, odometry, and inertial guidance). A first-rate map might lead you to your exit even when the exit sign is covered in snow.